A goal of drug development is delivering potent bio-therapeutic interventions that are specific for pathogenic cells, such as virus infected cells, neoplastic cells, cells producing an autoimmune response, and other dysregulated or dysfunctional cells without risk of toxicity to adjacent normal cells or the overall health of the patient. Unfortunately, developing these agents is extremely difficult.
A method that has emerged to allow delivery of potent interventions to pathogenic cells while mitigating toxicity to normal cells is targeting therapeutics against molecular markers specific for pathogenic cells. Targeted therapeutics have shown extraordinary clinical results in restricted cases, but are currently limited in their applicability due to a lack of accessible markers for targeted therapy. It is extremely difficult, and often impossible, to discover protein markers for many pathogenic cell types.
Existing nucleic acid-targeted therapies, such as siRNA, are able to down-modulate expression of potentially dangerous genes, but do not deliver potent cytotoxic or cytostatic interventions and thus are not particularly efficient at eliminating the dangerous cells themselves.
Hence, there exists a need to develop highly targeted therapeutics without the poor efficacy and/or severe side effects of existing interventions.